Bing has a New Feature- Search Images on any Website

Bing has a new feature that I have not found on Google. You can search all images on any websites.
I went on Bing.com image search and entered site:w3schools.com. This has resulted in all the images on www.w3schools.com. Its great!
But currently, it does not seems to return all images on website.
Google gave all images related with w3schools.com even if I have entered "site:" search operator.